Velocite filament wound rims

Everything about building wheels, glueing tubs, etc.
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vmajor
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by vmajor

No, it is not the same shape as the 507 as 77 gave us more depth to work with. Also the only goal that we gave to the AI that designed the 77 profile was to give us the lowest possible aerodynamic drag. Handling will be OK but since the 77 is not a general purpose wheel we prioritised low drag.

507 does have more turbulence at high yaw angles, but that is only when compared to the 77, not in general. The stall angle of the 507 is beyond 15 degrees yaw and it is very mild. "Conventional wisdom" does not actually work in the case of the 507 as there was nothing much like it before Bontrager released their homage range.

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Beaver
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by Beaver

The best aerodynamics will be achieved with a round torodial shape as seen on Zipp and Roval wheels - those are more affected by crosswinds though.

That shape allows a very low "wall thickness" on tradionally manufactured carbon rims, is this not possible with your technique?

The 507 shape was a compromise and for best crosswind stability a true teardrop shape as seen on Reynolds wheels is best. These cause more drag in high angles though.

Image

But the faster you go, the less these high angles will appear.

by Weenie


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vmajor
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by vmajor

...actually, yes, but it is not that simple. It is not the shape that matters. The shape is determined by the pressure gradient choices that are made while designing an airfoil. While the 507 looks superficially similar to Paul's (Lew) designs, I arrived at the 507 profile by trying to fit the desired pressure gradient into a 50mm deep rim. I will not go into too many more details even though Bontrager/Trek seem to have figured out what makes the resulting profile work.

Also the 507 rim profile does not have a sharp trailing edge, thus the side pressure/torque/thrust are lower than with the more pronounced edge.

Regarding the best aerodynamics resulting from the round torroidal shape, well yes in the past. Not with the wider tires though. The profile of the wider tire is too blunt. During the design of the 77mm rim the AI did actually create and consider several torroidal profiles, but they were all rejected in favour of the final result which is not torroidal.

Regarding the wall thickness, I am not sure I agree. I am not sure what Reynolds claims on this topic but that rim cutout looks like a manufacturing defect or just a result of a camera angle and light reflection off the edges and internal irregularities. Our thinnest sidewall rim is the Alter which has almost flat sides and thus creates an almost perfect box/rectangle section rim which is very stiff for its weight. Curved wall rims are always going to be vertically more compliant, but may offer greater torsional stiffness.

V.

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Beaver
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by Beaver

I only showed the Reynold cutout for the shape, not for wall thickness - those rims are also heavier than a round v-shape or torodial rim. ;)

And yes, the 507 and Paul Lews shape are different - he adopted the teardrop ("NACA") shape with the sharp trailing edge.

This shape is the most stable in crosswinds, but causes a few more watts drag in high angles.

Image Image

And Bontrager is indeed quite optimistic about their new round V-shape:

Image
http://trek.scene7.com/is/content/TrekB ... epaper.pdf

It will be more stable in crosswinds than a round torodial shape (which was one of their design goals) and interestingly they sticked with the round profile for their lowest rim as this won't be affected that much as the others (but even in their graph it is above the "optimal stability vs. drag line"...):

Image

So I am really curious for the first independent aero drag test. ;) Tour Mag. should do their yearly test in autumn.

The differences in the Bontrager test might only result from overlapping tires. The Bontrager are the widest and they simply "ignored" the wide Enve 3.4 SES... ;)

kuniyokeiji
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by kuniyokeiji

vmajor wrote:
Wed Jun 20, 2018 6:07 am
Disc brake wheels from the current batch are:

15 x 100mm through axle front
12 x 142mm through axle rear

Subsequent stock will come with the following:

12 x 100mm through axle front
12 x 142mm through axle rear

If the standard configuration is not suitable you can buy the adapters that you need here: https://shop.venn-cycling.com/index.php ... omponents/
hi vmajor
are those centrelock hubs?

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vmajor
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by vmajor

No they are not.

We are still trying to figure out the best way to transition to centrelock hubs. We will have some solution for this later this year and going forward.

V.

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MayhemSWE
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by MayhemSWE

kuniyokeiji wrote:
Thu Jun 21, 2018 12:48 pm
hi vmajor
are those centrelock hubs?
Just buy the rims, pick your favorite hubs and assemble yourself or have an LBS do it? I laced a pair of Rev 35 TCD rims onto DT Swiss 350 Classic centerlock hubs using DT Aerolite/Aero Comp spokes and Wheel Fanatyk splined nipples. Not difficult at all and it was only the second pair of wheels I ever built.

Hexsense
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by Hexsense

You can use adapter to convert from centerlock to fit 6 bolts rotor easily but not the otherway around,
Just move to centerlock and provides adapter for 6 bolts in the box should be good?

Harpoon
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Location: UK

by Harpoon

MayhemSWE wrote:
Thu Jun 21, 2018 2:56 pm
kuniyokeiji wrote:
Thu Jun 21, 2018 12:48 pm
hi vmajor
are those centrelock hubs?
Just buy the rims, pick your favorite hubs and assemble yourself or have an LBS do it? I laced a pair of Rev 35 TCD rims onto DT Swiss 350 Classic centerlock hubs using DT Aerolite/Aero Comp spokes and Wheel Fanatyk splined nipples. Not difficult at all and it was only the second pair of wheels I ever built.
Can I ask how you have found the rims and build? I've been suggested almost the same build by a wheel builder, bar CX-Ray spokes and the option of upgrading the ratchet in the hub. Have you tried them tubeless at all?

TheKaiser
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by TheKaiser

Harpoon wrote:
Thu Jun 21, 2018 9:58 pm
The option of upgrading the ratchet in the hub.
Unless you are using these for CX racing, I'd encourage you to skip the 36 or 54t ratchet upgrade. For MTB or CX having the rapid engagement is nice for getting the power down faster if you are on/off the pedals frequently on a twisty track, but for road/gravel that is more steady state the standard 18t ratchet engagement is fine, and is both quieter and lower drag (when coasting) than the higher tooth counts.

Harpoon
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by Harpoon

TheKaiser wrote:
Sat Jun 23, 2018 3:33 pm
Unless you are using these for CX racing, I'd encourage you to skip the 36 or 54t ratchet upgrade. For MTB or CX having the rapid engagement is nice for getting the power down faster if you are on/off the pedals frequently on a twisty track, but for road/gravel that is more steady state the standard 18t ratchet engagement is fine, and is both quieter and lower drag (when coasting) than the higher tooth counts.
Having listen to a few videos on Youtube since posting my question, I will probably avoid the upgrade as the noise of the 54t sounds quite annoying.

moonoi
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by moonoi

I've emailed Venn, but in case that anyone else has experienced a similar issue I thought I would ask here as well.

I bought the Venn Rev 507TCD late last year, ready for a build that was supposed to start in Jan, although the frame actually only arrived this week...

On trying to mount the front wheel, I am unable to get the thru axle to engage (It's Colnago own axle with hex lock, so I can't use the ones supplied with the wheels).

Looking at the end caps there appears to be a lip that the end caps on the rear wheel and wheels from other manufacturers don't have, making the outer diameter almost 21mm, whilst it should be 19mm when measured against the rear wheel and other wheels.

Image
Image

Kind of a bit puzzled to be honest, but this is the only thing I can find that would explain why they won't fit correctly.

Sent from my SM-G965F using Tapatalk


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vmajor
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by vmajor

Hi, sorry for missing your email, or did you just mail us? I think what you have is a 12mm through axle end cap that we made before the road disc 12mm through axle standard was finalized. You can order the end caps for a now standard road disc bike 12mm through axle here: https://shop.venn-cycling.com/index.php ... pter-kits/

If that is a 15mm through axle end cap, it looks like your fork is not standard so consider carefully machining down/applying a rasp to the end cap lips to make them fit into your fork as there are no alternative 15mm through axle end caps.

V.

moonoi
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by moonoi

vmajor wrote:
Mon Jul 16, 2018 10:01 am
Hi, sorry for missing your email, or did you just mail us? I think what you have is a 12mm through axle end cap that we made before the road disc 12mm through axle standard was finalized. You can order the end caps for a now standard road disc bike 12mm through axle here: https://shop.venn-cycling.com/index.php ... pter-kits/

If that is a 15mm through axle end cap, it looks like your fork is not standard so consider carefully machining down/applying a rasp to the end cap lips to make them fit into your fork as there are no alternative 15mm through axle end caps.

V.
Thanks Victor

Its a 12mm end cap that I specified when ordering the wheels end of December 2017, I had thought that the road disc thru axle standard had already been finalised at that point, but at least it does seem that the problem has been correctly identified.

I'll get these end caps machined down so the wheels can be used, and see about how to order the correct end caps and get them here, since shipping small items to Thailand is quite costly....EDIT, nice that you have flat rate shipping so I've placed an order via the website anyway.

Again much appreciated for the rapid reponse, and happy it wasn't me going mad then :D

by Weenie


Shuddup
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by Shuddup

Hi Victor,

Just got a pair of your Venn Rev 35 clincher wheels (very nice I must say). I was wondering how far from the rim should I set my brakes and I can't seem to find this information anywhere on your sites. You might perhaps consider either putting a temp marking showing this? Or having this information online. Thanks

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